Processing of radical prostatectomy specimens for correlation of data from histopathological, molecular biological, and radiological studies: a new whole organ technique

Abstract

Aims: To develop a method of processing non-formalin fixed prostate specimens removed at radical prostatectomy to obtain fresh tissue for research and for correlating diagnostic and molecular results with preoperative imaging.

Methods/results: The method involves a prostate slicing apparatus comprising a tissue slicer with a series of juxtaposed planar stainless steel blades linked to a support, and a cradle adapted to grip the tissue sample and receive the blades. The fresh prostate gland is held in the cradle and the blades are moved through the cradle slits to produce multiple 4 mm slices of the gland in a plane perpendicular to its posterior surface. One of the resulting slices is preserved in RNAlater. The areas comprising tumour and normal glands within this preserved slice can be identified by matching it to the haematoxylin and eosin stained sections of the adjacent slices that are formalin fixed and paraffin wax embedded. Intact RNA can be extracted from the identified tumour and normal glands within the RNAlater preserved slice. Preoperative imaging studies are acquired with the angulation of axial images chosen to be similar to the slicing axis, such that stained sections from the formalin fixed, paraffin wax embedded slices match their counterparts on imaging.

Conclusions: A novel method of sampling fresh prostate removed at radical prostatectomy that allows tissue samples to be used both for diagnosis and molecular analysis is described. This method also allows the integration of preoperative imaging data with histopathological and molecular data obtained from the prostate tissue slices.

Figure 1

Slicing of radical prostatectomy specimens. (A) The slicing device with juxtaposed parallel blades linked to a support and a handle (UK Patent Application Number 0318125.2). (B) The inked fresh prostate gland held in the cradle obtained from Lakeland Ltd (Cumbria, UK). (C) Slicing of a prostate held in the cradle with the slicing device. (D) Slices from a fresh prostate obtained with the help of the slicing device and cradle.

Figure 2

Integrated histopathology, molecular biology, and coordination with radiological imaging. (A) Left panel, research slice preserved in RNAlater^TM; middle panel, haematoxylin and eosin (H&E) histopathology section with arrows indicating areas of tumour; right panel, alignment of research slice and histopathology. (B) Left panel, research slice preserved in RNAlater and frozen at −70°C; middle panel H&E histopathology section with area of tumour marked with an arrow; right panel, RNA prepared from area of prostate cancer shown in the middle panel and subject to analysis on an Agilent Bioanalyser 2100 (Agilent Technologies, USA). (C) Left panel, fresh research slice; middle panel, H&E histopathology section with arrow indicating the location of the tumour; right panel, preoperative magnetic resonance image obtained from the same patient.

Figure 3

Histopathology from an RNAlater^TM preserved research slice. The research slice preserved in RNAlater was transferred to formalin as described in the text. (A) Low power (original magnification, ×4) and (B) high power (original magnification, ×20) haematoxylin and eosin stained images are shown. This illustrates that the tissue stored for research is adequately preserved for diagnostic pathology purposes, should it be needed.